Semiconductor devices are used widely in many applications, such as computers, televisions, home appliances, automobiles, cellular phones, and many other electrical and mechanical devices. Semiconductor devices are manufactured by depositing many thin layers of insulating, conductive, and semiconductor materials over a semiconductor substrate, and patterning the various layers using lithography.
There is a trend in the semiconductor industry towards downscaling or reducing the size of semiconductor features, in order to reduce the size and weight of the devices the semiconductor devices are used in, and to increased speed and decrease power consumption of devices, as examples. The thickness of material layers is also being decreased. Many material layers are extremely thin, for example, comprising only a few nanometers (nm) or Angstroms in thickness, for example.
The quality of a material layer of a semiconductor device is very important for device performance in order to achieve the device operation required. Unfortunately, the quality of some material layers may not be detectable until after the fabrication of a semiconductor device is completed, which results in entire lots of semiconductor devices needing to be scrapped, and further resulting in increased manufacturing time and costs. Furthermore, some tests to detect quality are destructive so that they may only be performed on samples of wafers, and the integrated circuits are destroyed in the test process.
Thus, what are needed in the art are improved methods and systems for evaluating the quality of material layers at various stages of a manufacturing cycle, e.g., part-way into a manufacturing cycle of a semiconductor device.